John Woodgate ) writes:

They are not so easy to obtain in small quantities. They were aimed at
high-volume consumer product manufacturers.

And that leads to another reason why they aren't used.

They are intended for very specific use, in something that will be
built in large quantities with the same design.

But what works for an AM/FM broadcast radio may not be best for some other
use.

I remember when RCA came out with the CA3088 AM receiver on an IC back
in 1971. QST ran an article about it, hinting at big things, yet also
pointint out deficiences. It was intended for a 455KHz IF, so you'd
be stuck with image problems as you started using the IC in the shortwave
range. I think there might have been limitations on the IF strip so
you couldn't run it at a higher frequency. The mixer was a single
transistor, and if I'm remembering, it was used as the local oscillator
also. Maybe okay in a generic broadcast receiver, but not great for
higher frequencies or where better performance was desired. The detector
was built in, and of course, it was AM only. There was no easy way to
bypass that detector, at a time when few hams would want to build an
AM only receiver.

In trying to fit a very specific application, it was lousy for more
general use.

Since then, there have been plenty of AM and AM/FM radios in an IC.
Some have worked better than others for other uses (who can forget
Ralph Burhan describing Loran C receivers using them?), mainly because
they were less integrated, or at least had pinouts in the right places.

Less grandiose ICs work better. The Motorola FM IF strips were at
first just the IF strip, and since they were intended for narrow band
FM, they were better suited for use in amateur applications. Even the
later variants, that added the front end, had the advantage that the
input and outputs were available off-IC so one could fiddle with things
where needed.

And then when you get to the point where an IC is simply taking care of
one stage, such as a mixer, or an IF amplifier, there is infinitely
more use of them in various designs. Of course, they are less useful
to mass marketers, because they take up more space and give more performance
than needed for AM/FM broadcast, so there is a limited market for them.

Michael VE2BVW

John Woodgate ) writes:

They are not so easy to obtain in small quantities. They were aimed at
high-volume consumer product manufacturers.

And that leads to another reason why they aren't used.

They are intended for very specific use, in something that will be
built in large quantities with the same design.

But what works for an AM/FM broadcast radio may not be best for some other
use.

I remember when RCA came out with the CA3088 AM receiver on an IC back
in 1971. QST ran an article about it, hinting at big things, yet also
pointint out deficiences. It was intended for a 455KHz IF, so you'd
be stuck with image problems as you started using the IC in the shortwave
range. I think there might have been limitations on the IF strip so
you couldn't run it at a higher frequency. The mixer was a single
transistor, and if I'm remembering, it was used as the local oscillator
also. Maybe okay in a generic broadcast receiver, but not great for
higher frequencies or where better performance was desired. The detector
was built in, and of course, it was AM only. There was no easy way to
bypass that detector, at a time when few hams would want to build an
AM only receiver.

In trying to fit a very specific application, it was lousy for more
general use.

Since then, there have been plenty of AM and AM/FM radios in an IC.
Some have worked better than others for other uses (who can forget
Ralph Burhan describing Loran C receivers using them?), mainly because
they were less integrated, or at least had pinouts in the right places.

Less grandiose ICs work better. The Motorola FM IF strips were at
first just the IF strip, and since they were intended for narrow band
FM, they were better suited for use in amateur applications. Even the
later variants, that added the front end, had the advantage that the
input and outputs were available off-IC so one could fiddle with things
where needed.

And then when you get to the point where an IC is simply taking care of
one stage, such as a mixer, or an IF amplifier, there is infinitely
more use of them in various designs. Of course, they are less useful
to mass marketers, because they take up more space and give more performance
than needed for AM/FM broadcast, so there is a limited market for them.

Michael VE2BVW

"Richard" wrote in
:

Although I have been interested an amateur radio for about 30 years,
I've never focused much attention on radios made with ICs.

Lately I have got an interest in FM receivers, and have discovered
some FM-related IC's/chipsets. ICs such as LA1177, LA1266, LM7000,
(these three being a chipset), and LA1235 etc etc.

But, doing a web search , you cannot find any homebrew AM/FM RX using
these IC's.

Why is this? I would have though they would be ideal for the hobbyist
to mess around with.



In the early 1970s, the electronics rags were loaded with IC projects.

The problem is that those ICs haven't been made since the early 1970s.

A tube never changes. I can buy a 6BA6 and buld the same RF amp that was
being built in the 1950s and 60s.

I can substitute a 6AU6 and it will still work.

I can use transistors and do the same thing.

An IC has internal "wiring" that is specific to it alone. If you can't get
that particular IC, you can't build the project.

On 28 Dec 2003 21:06:32 GMT, donutbandit wrote:

"Richard" wrote in
:

Although I have been interested an amateur radio for about 30 years,
I've never focused much attention on radios made with ICs.

Lately I have got an interest in FM receivers, and have discovered
some FM-related IC's/chipsets. ICs such as LA1177, LA1266, LM7000,
(these three being a chipset), and LA1235 etc etc.

But, doing a web search , you cannot find any homebrew AM/FM RX using
these IC's.

Why is this? I would have though they would be ideal for the hobbyist
to mess around with.



In the early 1970s, the electronics rags were loaded with IC projects.

The problem is that those ICs haven't been made since the early 1970s.

A tube never changes. I can buy a 6BA6 and buld the same RF amp that was
being built in the 1950s and 60s.

I can substitute a 6AU6 and it will still work.

I can use transistors and do the same thing.

An IC has internal "wiring" that is specific to it alone. If you can't get
that particular IC, you can't build the project.

Realistically, now-a-days, IC's are mostly "systems-on-a-chip", and
are usually custom-designed for a specific application; jelly-bean
analog chips (except perhaps OpAmps and linear voltage regulators) are
gradually fading from the scene.

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice480)460-2350 | |
| E-mail Address at Website Fax480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

On 28 Dec 2003 21:06:32 GMT, donutbandit wrote:

"Richard" wrote in
:

Although I have been interested an amateur radio for about 30 years,
I've never focused much attention on radios made with ICs.

Lately I have got an interest in FM receivers, and have discovered
some FM-related IC's/chipsets. ICs such as LA1177, LA1266, LM7000,
(these three being a chipset), and LA1235 etc etc.

But, doing a web search , you cannot find any homebrew AM/FM RX using
these IC's.

Why is this? I would have though they would be ideal for the hobbyist
to mess around with.



In the early 1970s, the electronics rags were loaded with IC projects.

The problem is that those ICs haven't been made since the early 1970s.

A tube never changes. I can buy a 6BA6 and buld the same RF amp that was
being built in the 1950s and 60s.

I can substitute a 6AU6 and it will still work.

I can use transistors and do the same thing.

An IC has internal "wiring" that is specific to it alone. If you can't get
that particular IC, you can't build the project.

Realistically, now-a-days, IC's are mostly "systems-on-a-chip", and
are usually custom-designed for a specific application; jelly-bean
analog chips (except perhaps OpAmps and linear voltage regulators) are
gradually fading from the scene.

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice480)460-2350 | |
| E-mail Address at Website Fax480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

"Richard" wrote in message
...
Although I have been interested an amateur radio for about 30 years, I've
never focused much attention on radios made with ICs.

Lately I have got an interest in FM receivers, and have discovered some
FM-related IC's/chipsets. ICs such as LA1177, LA1266, LM7000, (these
three
being a chipset), and LA1235 etc etc.

But, doing a web search , you cannot find any homebrew AM/FM RX using
these
IC's.

Why is this? I would have though they would be ideal for the hobbyist to
mess around with.

Okay, from what folks have said, I gather that as time has moved on, ICs
relevant to construction of AM/FM radios have tended, more and more, not to
appeal to homebrewers because their specs are seen as not being that good,
and they have lost much of their flexibility/applicability - due to current
design/production/marketing trends.

The NE602 is a favorite with the Ham crowd. Plenty of projects found on the
web, including FM.

Cheers

"Richard" wrote in message
...
Although I have been interested an amateur radio for about 30 years, I've
never focused much attention on radios made with ICs.

Lately I have got an interest in FM receivers, and have discovered some
FM-related IC's/chipsets. ICs such as LA1177, LA1266, LM7000, (these
three
being a chipset), and LA1235 etc etc.

But, doing a web search , you cannot find any homebrew AM/FM RX using
these
IC's.

Why is this? I would have though they would be ideal for the hobbyist to
mess around with.

In article , "Richard"
writes:

Although I have been interested an amateur radio for about 30 years, I've
never focused much attention on radios made with ICs.

Lately I have got an interest in FM receivers, and have discovered some
FM-related IC's/chipsets. ICs such as LA1177, LA1266, LM7000, (these three
being a chipset), and LA1235 etc etc.

But, doing a web search , you cannot find any homebrew AM/FM RX using these
IC's.

Why is this? I would have though they would be ideal for the hobbyist to
mess around with.

Yes, you CAN find the parts...those that survive after the 20 to 30 year
period from their new introduction until now. The MC3362 is a one-chip
FM receiver package available from Kits and Parts. Just add the dual
IF filters and support passives, perhaps a power audio IC for more
sound, maybe an RF stage for maximum sensitivity. Dieter has a
datasheet available for download on it if you like.

Problem is that few of those old ICs survive. They didn't sell well enough
to support continued production. Hundreds of IC designs have met that
fate, were successful, were produced, were sold. They just didn't sell
enough. A few were sold off to other semi makers (Fairchild got all of
the old National Semi digital line, for example...ON Semi got some of
the old Motorola ICs). About three "independent" semi makers in the
USA exist as second sources for old, obsolete semiconductors,
including specialty ICs. The old RCA Sommerville works and their
mighty CMOS line of both digital (CDxxxx) and analog (CAxxxx) got
partially picked up by Harris when RCA was sold to GE, but then
Harris sold off most of those to others, including Intersil and a few to
Maxim (according to part numbers and description).

What you, me, and many other hobbyists have to face is that the
scene in semiconductor ICs is CHANGING. There exist (and have
existed for at least a decade) "foundry" services to allow designs of
complex ICs that may be the entirety of a new electronic project.
Those won't even appear on the distributor market, just single
purchase lot of 100,000 or so, made, installed, and in a successful
product only to be succeeded by a changed, more competitive
device.

You CAN find out much with the right search words, including old
part numbers. Unfortunately, many of those old parts have become
"unobtainium" and exist only in archival datasheet records. A few
remain: MC3362, a one-chip FM receiver; SA602 and SA612 Gilbert
cell RF mixers; MC1350 low-VHF differential amplifier; several LMxxx
audio devices from National; MC145151 parallel-load PLL all-in-one;
CD4046 phase-freq detector for PLLs; 555 timers. The venerable
741 op-amp has long since been replaced by several general purpose
op-amps still produced by several makers. Many CDxxxx CMOS
digital devices are still available at very low prices (Jameco) and a
few CAxxxx analog CMOS are still there.

Outside of the Heathkits at the last decade of their existance, I
doubt you will find much in the way of articles and "plans" for a
homebuilt AM/FM receiver. When the already-manufactured article
costs less than the collection of parts needed to build one, why
bother? :-) If you want to build a special version for yourself, there's
a heaping glob of appnotes and datasheets for available components
on the web...but then you have to DESIGN something (true homebrew)
instead of copying someone else's design.

Len Anderson
retired (from regular hours) electronic engineer person

I read in sci.electronics.design that Richard nearlynews_email@ntlworld
..com wrote (in ) about
'Were IC's ever etensively employed in AM/FM RX homebrew projects?', on
Sun, 28 Dec 2003:
Lately I have got an interest in FM receivers, and have discovered some
FM-related IC's/chipsets. ICs such as LA1177, LA1266, LM7000, (these three
being a chipset), and LA1235 etc etc.

But, doing a web search , you cannot find any homebrew AM/FM RX using these
IC's.

Why is this? I would have though they would be ideal for the hobbyist to
mess around with.

They are not so easy to obtain in small quantities. They were aimed at
high-volume consumer product manufacturers.
--
Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk
Interested in professional sound reinforcement and distribution? Then go to
http://www.isce.org.uk
PLEASE do NOT copy news posts to me by E-MAIL!

"Richard" wrote in
:

Although I have been interested an amateur radio for about 30 years,
I've never focused much attention on radios made with ICs.

Lately I have got an interest in FM receivers, and have discovered
some FM-related IC's/chipsets. ICs such as LA1177, LA1266, LM7000,
(these three being a chipset), and LA1235 etc etc.

But, doing a web search , you cannot find any homebrew AM/FM RX using
these IC's.

Why is this? I would have though they would be ideal for the hobbyist
to mess around with.



In the early 1970s, the electronics rags were loaded with IC projects.

The problem is that those ICs haven't been made since the early 1970s.

A tube never changes. I can buy a 6BA6 and buld the same RF amp that was
being built in the 1950s and 60s.

I can substitute a 6AU6 and it will still work.

I can use transistors and do the same thing.

An IC has internal "wiring" that is specific to it alone. If you can't get
that particular IC, you can't build the project.